Phil.. Look at it this way. And maybe you can convince her of it. Most stunt bikes are ratted with broken plastics and a wheelie bar cut through the rear tail section and honestly dont look that nice. I think your reasoning for wanting this bike isnt to do crazy stunts on it considering the rarity of the model. Im not saying you wont do stunts but its like you wouldnt do stuff in your Z that you know there is a REALLY good chance of wrecking it. And on the injuries. I dont see any casts or splints or neck braces. So really whats the big deal? I raced motocross for over 13 years and will get back into it shortly(i miss it to much). And bruises are just a way of life.
Now take in mind im not married but one thing i do know is that she married YOU more than likely KNOWING you where a bike/stunter guy. Probably even liked it. Why do Girls always expect us to change just because we get older?